William Kahan
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William "Velvel" Morton Kahan (born June 5, 1933) is a Canadian mathematician and computer scientist, who is a professor emeritus at University of California, Berkeley. He received the Turing Award in 1989 for "his fundamental contributions to numerical analysis."<ref name=TuringAward>Template:Cite web</ref>
Biography
Born to a Canadian Jewish family,<ref name=TuringAward/> he attended the University of Toronto, where he received his bachelor's degree in 1954, his master's degree in 1956, and his Ph.D. in 1958, all in the field of mathematics. Kahan is now emeritus professor of mathematics and of electrical engineering and computer sciences (EECS) at the University of California, Berkeley.
Kahan was the primary architect behind the IEEE 754-1985 standard for floating-point computation (and its radix-independent follow-on, IEEE 854). He has been called "The Father of Floating Point", since he was instrumental in creating the original IEEE 754 specification.<ref name=TuringAward/> Kahan continued his contributions to the IEEE 754 revision that led to the current IEEE 754 standard.
In the 1980s he developed the program "paranoia", a benchmark that tests for a wide range of potential floating-point bugs.<ref>Template:Citation</ref> He also developed the Kahan summation algorithm, an important algorithm for minimizing error introduced when adding a sequence of finite-precision floating-point numbers. He coined the term "Table-maker's dilemma" for the unknown cost of correctly rounding transcendental functions to some preassigned number of digits.<ref>Template:Cite web</ref>
The Davis–Kahan–Weinberger dilation theorem is one of the landmark results in the dilation theory of Hilbert space operators and has found applications in many different areas.<ref>Template:Cite journal</ref>
He is an outspoken advocate of better education of the general computing population about floating-point issues and regularly denounces decisions in the design of computers and programming languages that he believes would impair good floating-point computations.<ref name=kahan_java>Template:Cite web</ref><ref name=kahan_interview>Template:Cite web</ref><ref>Template:Cite web</ref>
When Hewlett-Packard (HP) introduced the original HP-35 pocket scientific calculator, its numerical accuracy in evaluating transcendental functions for some arguments was not optimal. HP worked extensively with Kahan to enhance the accuracy of the algorithms, which led to major improvements. This was documented at the time in the Hewlett-Packard Journal.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> He also contributed substantially to the design of the algorithms in the HP Voyager series and wrote part of their intermediate and advanced manuals.
Kahan was named an ACM Fellow in 1994, and inducted into the National Academy of Engineering in 2005.<ref name=TuringAward/>
See also
References
External links
- William Kahan's home page
- An oral history of William Kahan, Revision 1.1, March, 2016
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- A Conversation with William Kahan, Dr. Dobb's Journal , November 1, 1997
- An Interview with the Old Man of Floating-Point, February 20, 1998
- IEEE 754 An Interview with William Kahan April, 1998
- Paranoia source code in multiple languages
- Paranoia for modern graphics processing units (GPUs) Template:Webarchive
- 754-1985 - IEEE Standard for Binary Floating-Point Arithmetic, 1985, Superseded by IEEE Std 754-2008
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- 1933 births
- Living people
- 20th-century Canadian mathematicians
- 21st-century Canadian mathematicians
- Numerical analysts
- Canadian computer scientists
- Scientific computing researchers
- UC Berkeley College of Engineering faculty
- Turing Award laureates
- 1994 fellows of the Association for Computing Machinery
- Scientists from Toronto
- University of Toronto alumni
- Canadian expatriate academics in the United States
- Jewish Canadian scientists